Letter 3369

Alodine 1201 versus Alodine 1200S 

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Customer call out Alodine 1201 [link is to product info at BoatersWorld] as a replacement for alodine 1200S. What is the difference between these products?

Best Regards, Menno Velthuijs.

Menno Velthuijs
- Nieuw Vennep, Holland, Europe

Alodine 1201 is a ready-to-use chromate conversion chemical; that is, for its original purpose there are no make-up or control parameters to be concerned about. In terms of U.S. military specifications, which many aircraft companies use as a guide, it is qualified under the Qualified Products List of MIL-C-81706 as a brush-on only. It was created primarily for touch-up and repair of scratched surfaces which had been previously anodized or chromated. If not tied into a specification such as the above, it can be diluted 1 part: 2 parts water to make an immersion bath for chromating new parts. As a bath it can be controlled like Alodine 1200S.

Alodine 1200S is a powder, chromate conversion chemical which must be dissolved in water to make a bath, which is then used to chromate aluminum. Under the QPL of MIL-C-81706 it is qualified for immersion, spray, or brush-on coatings. In terms of processing aircraft parts, AL 1200S has been the benchmark of the industry for over 40 years. Alodine 1201 is similar to a 20 gram per liter solution of Alodine 1200S. The AL 1200S can be used anywhere AL 1201 is used, but for large amounts of touch-up work or if handling of a liquid is preferred, AL 1201 is more convenient.

We are not aware of immersion baths of Alodine 1201 being used on a long-term basis, and if the reason for using it is strictly to handle liquids, we have another liquid product on the above QPL, Alodine 1600, which was designed for long- term use in immersion or spray baths.

Phil Johnson Madison Heights, Michigan